Coupler for electrical connectors

ABSTRACT

An electrical connector for interconnecting a first circuit board to a second circuit board that has a connector housing attachable to the first board, including a base plate in the vicinity of the first board with a plurality of openings for providing access to contact members on the first board; a floating terminal block cooperating with a plurality of individually resilient contacts that rely on normal forces to establish an electrical, flexible conductors extending between the base plate and the electrical contacts to establish an electrical connection between the first board and the second board; a biasing member positioned relative to the housing and the terminal block so that the terminal block, and the plurality of individually resilient contact elements are biased away from the housing, the biasing member exerting a spring force on the terminal block such that a mating force is established between the contacts and the second circuit board is established; and, a coupler for maintaining the relative positions connector to the mating circuit board.

With respect to the International Application as published on May 15,1997:

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to structures that can be incorporated into anelectrical connector in order to mechanically connect the connector to acomplementary component. The structure is particularly applicable toboard-to-board connectors, but not limited thereto.

2. Summary of the Prior Art

U.S. Pat. No. 5,324,206 discloses an electrical connector comprising apressure table floatably coupled to the connector housing andresiliently biased therefrom. This pressure table is operative to bias aflexible circuit against the surface of a mating circuit board.

In electrical connectors, it is necessary to establish not only anelectrical connection between the complementary contacts which may behoused in a terminal block or upon a printed circuit board; but also, tointerconnect mechanically the mating connector components to ensure thatthe electrical connection is not defeated. This has been accomplished inthe prior art in a number of manners, such as fasteners similar toscrews or clips, resilient latch arms on one of the connectors thatcooperate with lugs on the other connector, or external devices thatfunction to hold the two together. These structures typically work wellwhere there is a fairly large range of tolerance with respect to wherethe electrical interconnection may occur over the distance of mating thetwo connector components together. This would be the case where one ofthe contacts is a pin contact an the other contact is a receptaclecontact having spring arms to form a wiping interconnection with thepin, as anywhere along the pin would form a satisfactory connection. Inaddition, an interconnection of this type requires that a fairly largeload must be brought to bear on the mating connector in order to engagewhatever latching structure is being used. These two considerationscreate a problem where there is either not enough linear travelavailable to establish the desired interconnection or the matingcomponents are not capable of bearing the amount of force necessary toestablish the interconnection. An example might be where a daughter cardis to be mated with a mother board and for whatever reason the standardedge card connector is not satisfactory.

These short comings are met by providing an electrical connectoraccording to claim 1 for mating with a complementary component having amating face and a plurality of complementary contact members. Anembodiment of the connector comprising a terminal block having a frontface and a plurality of contact receiving regions therein for receivingcontacts that mate with the complementary contacts, a housing blockwherein the terminal block is disposed and a connector coupleroperatively associated with said terminal block for engaging an anchorfixed on the complementary component in order to mechanically couple theconnector and complementary component; the connector being characterizedin that: the connector is mounted upon the board such that the structuremay float in the direction of mating and the terminal block isresiliently biased by a resilient member relative the housing bock suchthat when the connector coupler is engaged with the anchor, the frontface of the terminal block together with the mating face for thecomplementary component.

This makes this connector coupler device especially useful where it isdesired to form the interconnection between a contact pad and a springcontact, such as that used in an interposer. This feature furtherisolates those forces necessary to hold the electrical connector withthe complementary component from the forces associated with thecontacting members. Finally, a connector of this type is especiallyuseful for board-to-board interconnections where contact pads may beused instead of contact pins. For example, in U.S. Pat. No. 4,895,521(incorporated herein by reference for all purposes) a co-axialconnection module is disclosed that is particularly suite for boardinterfaces, especially one disposed on a multi-level board. In this casea signal pad is surrounded by a ground pad such that complete shieldingis offered at the board. The module includes a conductive outer sleeve,a dielectric support element and a contact element having a springportion extending therefrom. The conductive sleeve being configured toengage the ground pad and the spring portion to abut the signal pad suchthat a true co-axial interconnection is formed. By incorporating modulesof this type into a connector having the aforedescribed structure,dimensional variations can be accommodated, mating force requirementsreduced and any mechanical set of the spring member minimized as theloading thereof is controlled.

SUMMARY OF THE INVENTION

It is an advantage of this invention that the connector coupler may beengaged to the anchor as the connector and complementary component arebeing mated so that the spring member establishes the mating forcestherebetween. It is another advantage of this invention that by havingthe contact members of the complementary component a said distance fromthe mating force and the contacts of the connector a said distance fromthe front face, electrical connection may be assured in a reliablemanner as the mating face will abut the front face, thereby fixing thedistance between contacts also.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an upper rear perspective view of the present inventionincorporated into a board-to-board interconnection system;

FIG. 2 is a conceptional schematic view of the workings of aboard-to-board connector of FIG. 1 showing a pre-mating "cocked"condition;

FIG. 3 is a conceptual schematic view similar to FIG. 2 showing thefirst mated position;

FIG. 4 is a conceptual schematic view similar to FIG. 3 showing thefully mated position;

FIG. 5 is a conceptual schematic view showing initial de-mating;

FIG. 6 is a conceptual schematic view showing the first de-matedposition that corresponds to the mated condition of FIG. 3;

FIG. 7 is a conceptual schematic view showing the fully de-matedposition that corresponds to the pre-mated or "cocked" condition of FIG.2;

FIG. 8 is a conceptual schematic view showing attempted mating of theconnector when not in the pre-mated or "cocked" condition;

FIG. 9 is a side cross-sectional view corresponding to FIG. 2 showingthe electrical connectors of FIG. 1 ready for attachment;

FIG. 10 is a side cross-sectional view corresponding to FIG. 3 showingthe connector of FIG. 9 initially coupled to anchors on the matingcomponent;

FIG. 11 is a side cross-sectional view corresponding to FIG. 4 showingthe connector engaged as in FIG. 1;

FIG. 12 is a side cross-sectional view corresponding to FIG. 5 showingthe connector being disengaged from the anchors on the board;

FIG. 13 is a corresponding side cross-sectional view as the anchorsdisengage from the connector coupling members; and,

FIG. 14 shows a side cross-sectional view showing attempted mating wherethe connector couplers are not in a cocked position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference first to FIG. 1, a board-to-board interconnection isshown generally at 1. The board-to-board interconnection 1 includes amotherboard 2 and a daughter card 4. The daughtercard 4 has upper andlower surfaces 6,8 with electrical connectors 10 that incorporate thepresent invention therein. It is important to note that the invention isbeing described with reference to a board-to-board connection system 1where it is especially advantageous but the invention is not limited tosuch applications.

The motherboard 2 is a complementary component having a mating face 12thereupon. As would be typical in printed circuit board construction,the motherboard 2 would include circuit traces and components upon themating face 12 and a plurality of complementary contact members (notshown) forming an electrical interconnection with the mating componentor daughter card 4. The motherboard 2 further includes anchors 14 fixedto and extending therefrom.

With reference still to FIG. 1, the daughtercard 4 carries a pair ofconnectors 10 that are interconnected on opposite faces 6,8 thereof. Inthe embodiment shown, each connector 10 is made up of a base plate 16that lies fixed against the corresponding face 6,8 and includes aplurality of openings 18 for providing access to the contact members(not shown) disposed upon the daughter card 4 by flexible conductormembers 20. The conductor members 20 extend from the base plate 16 intoa housing block 22 where they are connected to contact modules (notshown). These contact modules may be advantageously formed asinterposer-style contacts that rely on a normal force establishedperpendicularly to the corresponding mating faces 12,24 to establish anelectrical interconnection such as those disclosed in U.S. Pat. No.4,895,521. Another example of an acceptable contact is disclosed in U.S.Pat. No. 5,228,861.

The housing block 22 contains a resiliently biased and floating terminalblock 23 that has a front face 24 that can be seen abutting the matingface 12 of the motherboard 2. At each end 26,28 of the housing block 22are connector couplers 30. The connector couplers 30 will be describedin greater detail below. The housing block 22 is slidably affixed to thebase 16 by way of complementary dove-tail structure including a maledove-tail 32 as part of the base 16 and a female dove-tail slot 34 aspart of the housing block 22. This provides that the housing block 22with float along the dove-tail strucure 32,34. It may be possible to useother mechanical couplings as an alternative to the dove-tail that limitthe motion therebetween to a single degree of freedom. Additionally, theterminal block 23 may be similarly mounted to the base 16 (freefloating) upon the dove-tail 32 or coupled only to the housing block 22through dove-tails formed in the sidewalls thereof. The terminal block23 has a releasable latch mechanism between the housing block 22 and theterminal block 23 such that they are selectively coupled. Furthermore, aresilient member or spring acts between the block 22,23 to bias theterminal block 23 from the housing block 22 as will be described below.Note, the amount of float of either block 22,23 may be limited by stopor latch structure (not shown) therebetween.

The invention is best described with reference to the conceptualschematic views shown in FIGS. 2-8, where FIGS. 2-5 show the matingsequence, FIGS. 5-7 show the demating sequence and FIG. 8 shows a failsafe feature where the connector 10 is prevented from mating unless in a"cocked" position. In these Figures, the representations correspondingto the features described above are numbered in the 100 series in acorresponding manner and the conceptual features, separately, are allwithin the basic mechanical arts and may be achieved in various ways.

With reference now to FIG. 2, the connector 110 is mounted upon thedaughter card 104 by the base plate 116 with the terminal block 122disposed within the housing block 22 such that it is free to movelongitudinally relative thereto as established by the dove-tails 40. Thehousing block 22 and the terminal block 23 are slidably coupled relativeeach other and to the base 116, for example by way of the dove-tails 132and 140, such that the housing block 122 is free to move axially uponthe daughtercard 104 and the terminal block 123 is free to move axiallyrelative the housing block 122 in the direction of insertion F. The base116 further includes stops 143 that are used to limit the displacementof the terminal block 123 as will be described below. The terminal block123 and the housing block 122 are joined together by a resilient member144 and at a releasable latching mechanism consisting of a latch arm 145and a catch 146 affixed to the terminal block 122 and the housing block123 respectively. The releasable latching structure may take on anynumber of forms as are well known in the mechanical arts. Additionally,a connector coupler 130 is attached to the housing block 122 forengaging the anchor 114 of the mother board 102.

With the releasable latch mechanism positioned such that the latch arm145 is retained by the catch 146, as shown in FIG. 2, the daughter card104 is inserted in the direction of force F. With reference now to FIG.3, insertion in the direction force F continues until the couplingmember 130 engages the anchor 114. At this engagement point, the face124 of the terminal block 123 is separated from the face 112 of themotherboard 102. As a result of the stop surface 143 upon the base 116and the coupled releasable latch mechanism 145,146 sufficient force maybe generated to engage the coupling member 130 with the anchor 114. Asthe coupling member 130 is relatively stiffly joined to the housingblock 122, it is not possible for additional force in the direction ofarrow F to bring the mating faces 124,112 into engagement.

With reference now to FIG. 4, once the connector is positioned as inFIG. 3, the releasable latch members 145,146 are disengaged, for exampleby a mechanical feature that separates the coupling, such that theterminal block 123 is disposed such that the mating faces 124,112 areabutting as a result of the resilient member 144. Additionally, acertain amount of manufacturing tolerances in the positioning and thesizes of the components may be accommodated by the variation A. Withinthis region, it is possible for the resilient member 144 to exertroughly the same amount of force at the mating face interface 124,112.Additionally, in this configuration, there is no force link between theterminal block 123 and the daughter board 104 such that the terminalblock 123 is essentially free floating relative thereto and biasedagainst the mother board 102 by the spring force of the resilient member144 that is coupled to the housing block 122 which is anchored to themother board 102 by coupling member 130.

With respect now to FIGS. 5-7, the demating sequence will be described.With reference first to FIG. 5, upon the exertion of a removal force F',the daughter card 4 is withdrawn such that the base unit 116 movesrelative the terminal block 123 until the front step 143 becomes engagedtherewith. Additional displacement in the withdrawal direction F'results in the base member 116 carrying the terminal block 123 rearwarduntil the releasable latch members 145,146 engage (FIG. 6). Upon furtherextraction in the withdrawal direction F', the coupling member 130disengages from the anchor 114. In this position, the connector 10 wouldbe ready for mating on the next insertion.

With reference now to FIG. 8, if the "cocked" position of FIG. 7 andFIG. 2 is not established be for mating, the condition shown in FIG. 8will occur. The lack of engagement between the releasing latch mechanism145,146 prevents the coupling member 130 from engaging the anchor 114 asthe housing block 122 will travel rearward with the terminal block 123in response to insertion in the direction of arrow F. This "stubbing" ofthe "non-cocked" connector 110 assures that proper mating forces areestablished such that the interposer-style contacts in the mating face124 achieve proper mating with the contact pads 112 of the motherboard102.

With reference now to FIGS. 9-14, a connector coupling structure and theworkings thereof will be described in greater detail. The anchor members14 that extend from the mating face 12 of the motherboard 2 aremechanically retained therein by conventional means such as soldering orpress-fit interference. The anchors 14 include a bulbous head portions31 generally spherical in shape that extend beyond a pin body 34. Withreference now to the connector 10, the connector coupler 30 is disposedwithin a cavity 36 of the housing block 22 and includes a couplingmember 38 operatively connected to the housing block 22 by a resilientmember 40 which, in this example, is a simple coil spring. The coupler38 includes a forward section 42 having a receptacle region 44configured to generally correspond to the head 31 of the anchor 14. Theforward portion 42 is divided into multiple resilient fingers 46 thatare deflectable to enable the head 32 to enter the receptacle 44.Opposite the forward portion 42 is a rearward section 48 having multipleresilient arms 48. The resilient arms 48 enable the coupler 38 to bepressed into the cavity 36 and then retained beneath a shoulder 52. Thecavity 36 further includes a front portion 54 wherein the forwardportion 42 of the coupler 38 is received. The coupler 38 is slidablewithin the cavity 36 between a position (as shown in FIG. 9) where thecoil spring 40 is fully compressed and a relaxed position where the rearportions 40 abut the shoulder 52 (FIGS. 11 and 14).

With further reference to FIG. 9, the electrical connectors 10 are shownwith the terminal block 23 biased forward along the dove-tail 32 and thecoupler members 38 biased forward within the cavity 36 so that theforward end 42 of the coupler 30 is extending from a stepped face 56 ofthe housing block 22. In this position, the resilient fingers 46 of thefront end 42 of the coupling member 38 are free from the forward portion54 of the cavity 36 and may deflect outward so that the head 31 mayenter the receptacle 44. Once the head 31 is in the receptacle 44, thespring force of the coil spring 40 may be released and the arms 46 mayreturn into the cavity 36 with the head 31 retained therein, as bestshown in FIG. 11. Various mechanical structures may be used to effectthe release, such as a release button coupled thereto or a ball-pointpen push release.

With reference now to FIG. 10, as may be observed, the daughterboard 4and the associated connectors 10 have been initially fixed to themotherboard 2. In the case the heads 31 of the anchors 14 are engagedwithin the receptacle portion 44 of the couplers 38. Due to the forceexerted by the coil springs 40, the coupling members 38 are graduallybeing drawn back as the daughterboard 4 moves forward towards themotherboard 2. Provided the components are properly configured anddimensioned, the front face 24 of the terminal block 23 abuts the matingface 12 of the motherboard 2 upon release of the latch mechanism 45,46.This may be best seen in FIG. 11. The terminal block 23 and housingblock 22 having coupler members 30 therein are also resiliently coupled.

With reference now to FIG. 11, the connector 10 on the daughterboard 4has been brought into a fully mated position with the motherboard 2 suchthat the front face 24 is against the mating face 12. In this position,the head 32 of the anchor 14 is within the receptacle 44 and the fingers46 of the front end 42 are fully retracted within the forward portion 54of the cavity 36, thereby the fingers 46 are prevented from expanding bythe close fit within the forward portion 54. The cooperation of theforward portion 54 and fingers 46 assure that the connector coupler 30remains engaged with the anchor 14. Also, the force which the connectorface 24 abuts the mating face 12 of the motherboard 2 is directlyrelated to the spring members 40 and where used, the resilient member 44as shown in FIGS. 2-8. As may be further imagined, it is easy to seethat the spring members 40 may be used to draw the two components 2,4together without the need to exert an insertion force against themotherboard 2 as the daughter card 4 is being mated therewith.

With reference now to FIGS. 12 and 13, removal of the daughter card 4from the motherboard 2 will be described. By exerting a force on thedaughtercard 4 in the direction arrow F' of FIG. 6, the force exerted bythe springs 40 is overcome. In doing so, the outer housing 22 of theconnectors 10 will be pulled away from the motherboard 2 and thecouplers 38 will remain affixed to the anchors 14 until the forward end42, and in particular the resilient fingers 46, pass the face 56 so thatthey are free of the forward portion 54 of the cavity 36. At this pointthe couplers 38 are retained in the cavity 36 in the cocked position ofFIG. 9. Further exertion of the force will result in the resilientfingers 46 opening about the head 31 of the anchor 14 and releasingtherefrom. As shown in FIG. 13, the coupler 38 will then be pulled backby spring member 40 and the daughtercard 4 will be free from themotherboard 2. With reference to FIG. 14, unless the couplers 38 are inthe cocked position of FIG. 9, it will not be possible to engage theanchors 14. This provides a similar "stubbing" to that described above.

Initially, a special tool could be brought against the coupler members38 to bias them forward into the position shown in FIG. 9. The couplers138 would then be locked in this position.

While the afore going has been described generally with respect to aboard-to-board interconnection 1, it should be apparent that the generalprinciples of the anchor 14 and the coupling mechanism to isolate forcescould be transferred to other connector applications. In addition, whileparticular contact structure has not been described in detail it shouldbe apparent that numerous designs would be acceptable, including theafore mentioned "interposer" style interconnection where a spring membercontact is biased against a contact pad without mechanically embracingthe pad. Advantageously, for high performance, each signal contact issurrounded by a ground contact. Furthermore, while the jumpers 20 havebeen shown entering from the rear of the terminal block 23 above, it mayalso be possible to utilize side entry.

We claim:
 1. An electrical connector for mating with a complementarycomponent having a mating face and an anchor, the connector comprisesaconnector housing having a connector coupler therein for engaging theanchor in a fixed manner and a terminal block for receiving individualcontact modules, with resilient contacts, therein and arrangedcomplementarily to the mating face, wherein the terminal block isfloatably coupled to the connector housing and resiliently biasedtherefrom by a resilient member such that the coupling force at themating face is determined by the force of the resilient member.
 2. Theconnector of claim 1, wherein the connector housing and terminal blockinclude a releasable latch therebetween such that the terminal block isheld back from the mating face until the coupler engages the anchor. 3.The connector of claim 1, wherein the connector housing is floatablymounted on a substrate such that when the substrate and thecomplementary component are mated, the mating force at the complementarycomponent is determined by the resilient member relatively independentof the position of the substrate relative the complementary component.4. The connector of claim 2, wherein the connector housing and theterminal block must be latched together in order for the coupler toengage the anchor such that the mating occurs, thereby preventingpushback or stubbing.
 5. The connector of claim 3, wherein the coupleris spring loaded.
 6. The connector of claim 4, wherein the latch isre-engaged upon demating.
 7. An electrical connector for mounting to afirst board to establish an interconnection to a second board having amating face thereupon, where an anchor is provided for positioning theelectrical connector relative the second board, the electrical connectorcomprising:a connector housing attachable to the first board, includinga base plate to be positioned in the vicinity of the first board andincluding a plurality of openings for providing access to contactmembers on the first board; a floating terminal block for carrying aplurality of individually resilient contacts that rely on normal forcesestablished perpendicularly to the mating face to establish anelectrical connection with the mating face of the second board, flexibleconductors extending between the base plate and the terminal block tothe establish the electrical connection between the first board and thesecond board; and, a biasing member positioned relative the housing andthe terminal block so that the terminal block is biased away from thehousing, the biasing member exerting a spring force on the terminalblock such that a mating force is established; and a coupler forengaging the anchor in a fixed manner.
 8. The electrical connector ofclaim 7, wherein the biasing member is a coil spring.
 9. The electricalconnector of claim 8, wherein the positioning of the electricalconnector relative the mating face of the second board is determined bya pin-and-socket structure incorporated into the connector and thesecond board.
 10. The electrical connector of claim 9, wherein theanchor and the coupler are also the pin-and-socket structure.
 11. Theelectrical connector of claim 7, wherein when the anchor and the couplerare engaged, the biasing member causes a mating force to be exerted onthe terminal block and through to the mating face of the second board,the mating force being relatively independent of the positioning of theelectrical connector and the second board.
 12. An electrical connectorfor interconnecting a first circuit board to a second circuit boardwhere the connector is adapted to be mounted to the first circuit boardand the second circuit board is provided with an anchor, the electricalconnector comprising:a connector housing attachable to the first board,including a base plate to be positioned in the vicinity of the firstboard and including a plurality of openings for providing access tocontact members on the first board; a floating terminal blockcooperating with a plurality of individually resilient contacts thatrely on normal forces established perpendicularly to the mating face toestablish an electrical connection with the mating face of the secondboard, flexible conductors extending between the base plate and theelectrical contacts to establish an electrical connection between thefirst board and the second board; a biasing member positioned relativethe housing and the terminal block so that the terminal block, and theplurality of individually resilient contact elements are biased awayfrom the housing, the biasing member exerting a spring force on theterminal block such that a mating force is established between thecontacts and the second circuit board is established; and, a coupler forengaging the anchor in a fixed manner.